Abstract 12431: Fragmented Left Ventricular Activation on Magnetocardiography Can Predict Adverse Cardiac Events in Dilated Cardiomyopathy Patients with Narrow QRS Duration
Background: In patients with non-ischemic dilated cardiomyopathy (DCM), fragmented QRS (fQRS) on 12-lead ECG associated with myocardial scar has been show to be an independent predictor of cardiac event as well as in ischemic cardiomyopathy, even if QRS duration is normal. Furthermore, it is known that fQRS reflects regional electrical heterogeneity in arrhythmogenic substrates. However, the problem is that this fragmentation is too subtle to identify and its definition remains to be established. We thus hypothesized that multi-channel magnetocardiography (MCG) with high spatio-temporal resolution can sensitively disclose abnormal QRS components (intraventricular conduction) corresponding to fQRS on ECG and that it would predict adverse cardiac events in patients with non-ischemic DCM (LVEF <35%) with narrow QRS duration (QRSd <120ms).
Methods: In 43 DCM patients (LVEF 22±7%, QRSd 100±10ms), we recorded 64-Ch MCGs to derive QRS current arrow maps and vector magnitude waveforms (VMW). Fragmented LV activation (fLV) was defined as a discrete component (>20% of Max amplitude) on VMW corresponding to heterogeneous LV conduction on QRS mapping. Long term follow-up was conducted with regard to major adverse cardiac event (MACE; cardiac death, sustained VT or VF, and hospitalization for heart failure).
Results: fLV was found in 25 (Group-A) and in 18 (Group-B). Age, gender, QRSd, LVDd, Ds, EF, BNP and serum creatinine were comparable between the groups. During a mean follow-up of 600 days, MACE occurred in 17 (2 death, 7 arrhythmic events, and 8 hospitalizations). Kaplan-Meier event-free analysis revealed that MACE more frequently occurred in Group-A (60%, 15/25) than in Group-B (11%, 2/18, p=0.02).
Conclusions: MCG analysis is a promising noninvasive tool for sensitively disclose abnormal left intraventricular conduction in non-ischemic DCM patients with narrow QRS. The finding may serve to predict future adverse event.
- © 2012 by American Heart Association, Inc.